Cellular communication system having antenna array with enhanced half-power beamwidth control

Abstract

The present disclosure relates to a cellular communication system having an antenna array with enhanced half-power beamwidth control. The antenna array includes a first plurality of radiating elements in a first column thereof, the first plurality of radiating elements responsive to a first plurality of RF feed signals derived from a first radio, and a second plurality of radiating elements in a second column thereof, the second plurality of radiating elements responsive to a second plurality of RF feed signals derived from a second radio. A power divider circuit is provided, the power divider circuit being configured to drive a first radiating element at a first end of the second column of radiating elements with a majority energy associated with a first one of the first plurality of RF feed signals and to drive a first radiating element at a first end of the first column of radiating elements with a non-zero minority energy associated with the first one of the first plurality of RF feed signals.

Description

[0001] Citation of priority application

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 882,052, filed on August 2, 2019, the disclosure of which is hereby incorporated by reference herein. Technical Field

[0003] The present invention relates to radio communications and antenna arrangements, and more particularly to a base station antenna array for cellular communications and a method of operating a base station antenna array. Background Art

[0004] Phased array antennas can create and electronically steer radio wave beams in different directions without physically moving the radiating elements therein. As shown in FIG1A , in a phased array antenna 10, radio frequency (RF) feed current is provided from a transmitter (TX) to a plurality of spaced-apart antenna radiating elements through phase shifters (Φ1-Φ8), which establish a desired phase relationship between the radio waves emitted by the spaced-apart radiating elements. As will be understood by those skilled in the art, the properly established phase relationship enables the radio waves emitted from the radiating elements to combine to enhance radiation in a desired direction (shown as θ) but suppress radiation in undesirable directions. Phase shifters (Φ n ) is typically controlled by a computer control system (CONTROL) that can change the phase of the transmitted radio waves and thereby electronically steer the combined waves in different directions. This electronic steering can be important when phased array antennas are used for cellular communications and other RF-based systems.

[0005] For example, in a typical cellular communication system, a geographic area is generally divided into a series of areas, generally referred to as "cells", which are served by corresponding base stations. Each base station may include one or more base station antennas (BSA) configured to provide two-way radio frequency ("RF") communications with mobile users within the cell served by the base station. In many cases, each base station is divided into "sectors". In perhaps the most common configuration, the hexagonal-shaped cell is divided into three 120° sectors, each sector being served by one or more base station antennas, which may have an azimuth half-power beamwidth (HPBW) of approximately 65° per sector. Typically, the base station antenna is mounted on a tower or other elevated structure with the radiation pattern (also known as an "antenna beam") directed outward therefrom. The base station antenna is typically implemented as a linear or planar phased array of radiating elements. For example, as shown in FIG. 1B , the base station antenna 10' may include a side-by-side array (RE) of radiating elements. 11 -RE 18 、RE 21 -RE 28), these side-by-side arrays define a pair of relatively closely spaced antennas A1 and A2. In this base station antenna 10', each column of radiating elements is responsive to a respective phase-shifted feed signal derived from a corresponding RF feed signal (FEED1, FEED2) and transmitter (TX1, TX2), and varied in response to computer control (CONTROL1, CONTROL2).

[0006] To accommodate the growing volume of cellular traffic, cellular operators have been adding cellular services in a variety of new frequency bands. While in some cases, a linear array of so-called "wideband" or "ultra-wideband" radiating elements can be used to provide service in multiple frequency bands, in other cases, different linear arrays (or planar arrays) of radiating elements must be used to support services in different frequency bands.

[0007] With the surge in the number of frequency bands, increasing sectorization has become more common (e.g., dividing a cell into six, nine, or even twelve sectors), and the number of base station antennas deployed at a typical base station has increased significantly. However, due to local zoning regulations and / or weight and wind load constraints on the antenna tower, there are often restrictions on the number of base station antennas that can be deployed at a given base station. In order to increase capacity without further increasing the number of base station antennas, so-called multi-band base station antennas have been introduced, in which multiple linear arrays of radiating elements are included in a single antenna. A very common multi-band base station antenna design is the RVV antenna, which includes: one linear array of "low-band" radiating elements for providing service in some or all of the 694-960 MHz frequency band (commonly referred to as the "R-band"); and two linear arrays of "high-band" radiating elements for providing service in some or all of the 1695-2690 MHz frequency band (commonly referred to as the "V-band"). These linear arrays of R-band and V-band radiating elements are typically mounted in a side-by-side manner.

[0008] There is also great interest in RRVV base station antennas, which may include two linear arrays of low-band radiating elements and two (or four) linear arrays of high-band radiating elements. For example, as shown by FIG1C , the RRVV antenna 12 may include two outer columns 14a, 14b of relatively low-band radiating elements (each column shown as 5 "large" radiating elements ("X")) and two inner columns 16a, 16b of relatively high-band radiating elements (each column shown as 9 "small" radiating elements ("x")). The RRVV antenna may be used in a variety of applications, including 4x4 multiple-input multiple-output ("MIMO") applications, or may be used as a multi-band antenna having two different low-bands (e.g., a 700 MHz low-band linear array and an 800 MHz low-band linear array) and two different high-bands (e.g., an 1800 MHz high-band linear array and a 2100 MHz high-band linear array). However, RRVV antennas are challenging to implement in a commercially acceptable manner because achieving a 65° azimuth HPBW antenna beam in the low band typically requires a low band radiating element that is at least 200 mm wide. However, as shown in FIG1C , when two arrays of low band radiating elements are placed side by side with a high band linear array between them, a base station antenna with a width of approximately 500 mm may be required. Such a large RRVV antenna may have very high wind loading, may be very heavy, and / or may be expensive to manufacture. Operators prefer RRVV base station antennas with a width of approximately 430 mm, which is a typical width of prior art base station antennas.

[0009] To achieve an RRVV antenna with a narrower beamwidth, the size of the low-band radiating element can be reduced and / or the lateral spacing between the linear arrays of low-band "R" and high-band "V" radiating elements can be reduced. Unfortunately, as the linear arrays of radiating elements are packed closer together, the degree of signal coupling between the linear arrays can increase significantly, and this "parasitic" coupling can lead to an undesirable increase in HPBW. Similarly, any reduction in the size of the low-band radiating element will generally result in an increase in HPBW. Summary of the Invention

[0010] An antenna array according to some embodiments of the present invention may include: a first column of radiating elements and a second column of radiating elements, the first column of radiating elements and the second column of radiating elements being responsive to a first plurality of radio frequency (RF) feed signals derived from a first radio and a second plurality of RF feed signals derived from a second radio, respectively. A first power divider circuit is provided, the first power divider circuit being configured to drive a first radiating element in the second column of radiating elements with a majority energy associated with a first one of the first plurality of RF feed signals and to drive the first radiating element in the first column of radiating elements with a non-zero minority energy associated with the first one of the first plurality of RF feed signals. In these embodiments, the first radiating element in the first column of radiating elements may extend diametrically opposite the first radiating element in the second column of radiating elements. The first power divider circuit may also be configured to drive the first radiating element in the first column of radiating elements with a majority energy associated with the first one of the second plurality of RF feed signals and to drive the first radiating element in the second column of radiating elements with a non-zero minority energy associated with the first one of the second plurality of RF feed signals.

[0011] In a further embodiment of the present invention, a second power divider circuit may be provided, the second power divider circuit being configured to drive the second radiating element in the first column of radiating elements with a majority energy associated with the second one of the first plurality of RF feed signals and to drive the second radiating element in the second column of radiating elements with a non-zero minority energy associated with the second one of the first plurality of RF feed signals. This second power divider circuit may also be configured to drive the second radiating element in the second column of radiating elements with a majority energy associated with the second one of the second plurality of RF feed signals and to drive the second radiating element in the first column of radiating elements with a non-zero minority energy associated with the second one of the second plurality of RF feed signals.

[0012] According to yet further embodiments of the present invention, a first phase shifter is provided, configured to generate a first plurality of RF feed signals in response to a first RF input feed signal generated by a first radio. A second phase shifter may also be provided, configured to generate a second plurality of RF feed signals in response to a second RF input feed signal generated by a second radio. Thus, the first plurality of RF feed signals may be phase-shifted relative to one another, and the second plurality of RF feed signals may be phase-shifted relative to one another.

[0013] According to an additional embodiment of the present invention, a second radiating element in the first column of radiating elements receives all energy associated with a second one of the first plurality of RF feed signals, and a second radiating element in the second column of radiating elements receives all energy associated with a second one of the second plurality of RF feed signals. Thus, the second radiating element in the first column of radiating elements may not receive energy associated with the second plurality of RF feed signals, and the second radiating element in the second column of radiating elements may not receive energy associated with the first plurality of RF feed signals.

[0014] In yet other embodiments of the present invention, an antenna array is provided having a first array of radiating elements and a second array of radiating elements, the first array of radiating elements and the second array of radiating elements being responsive to a first plurality of radio frequency (RF) feed signals derived from a first RF transmitter and a second plurality of RF feed signals derived from a second RF transmitter, respectively. A first power divider circuit is provided, the first power divider circuit being configured to: (i) drive a first radiating element in the second array of radiating elements with a majority energy associated with a first one of the first plurality of RF feed signals; (ii) drive the first radiating element in the first array of radiating elements with a non-zero minority energy associated with the first one of the first plurality of RF feed signals; (iii) drive the first radiating element in the first array of radiating elements with a majority energy associated with the first one of the second plurality of RF feed signals; and (iv) drive the first radiating element in the second array of radiating elements with a non-zero minority energy associated with the first one of the second plurality of RF feed signals. The antenna array may be further configured such that a second radiating element in the first array of radiating elements receives all energy associated with a second of the first plurality of RF feed signals, and a second radiating element in the second array of radiating elements receives all energy associated with a second of the second plurality of RF feed signals.

[0015] Alternatively, a second power divider circuit may be provided, the second power divider circuit being configured to drive a second radiating element in the first array of radiating elements with a majority energy associated with a second one of the first plurality of RF feed signals and to drive a second radiating element in the second array of radiating elements with a non-zero minority energy associated with the second one of the first plurality of RF feed signals.

[0016] According to an additional embodiment of the present invention, an antenna array is provided, comprising: a first plurality of radiating elements in a first column, the first plurality of radiating elements responsive to a first plurality of RF feed signals derived from a first radio; and a second plurality of radiating elements in a second column, the second plurality of radiating elements responsive to a second plurality of RF feed signals derived from a second radio. A power divider circuit is provided, the power divider circuit being configured to drive a first radiating element at a first end of the second column of radiating elements with a majority of energy associated with a first one of the first plurality of RF feed signals, and to drive a first radiating element at a first end of the first column of radiating elements with a non-zero minority of energy associated with the first one of the first plurality of RF feed signals. The first power divider circuit can also be configured to drive a first radiating element in the first column of radiating elements with a majority of energy associated with the first one of the second plurality of RF feed signals, and to drive a first radiating element in the second column of radiating elements with a non-zero minority of energy associated with the first one of the second plurality of RF feed signals. Furthermore, a second radiating element in the first column of radiating elements can be driven with all of the energy associated with a second one of the first plurality of RF feed signals, and with no energy associated with the second one of the second plurality of RF feed signals. Similarly, a second radiating element in the second column of radiating elements may be driven with all of the energy associated with the second of the second plurality of RF feed signals and with no energy associated with the second of the first plurality of RF feed signals. In some of these embodiments of the invention, the second radiating element in the first column of radiating elements may be located at a second end of the first column of radiating elements, and the second radiating element in the second column of radiating elements may be located at a second end of the second column of radiating elements. In some of these embodiments of the invention, the first and second columns of radiating elements are arranged such that each radiating element in the first column of radiating elements extends diametrically opposite a corresponding radiating element in the second column of radiating elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1A is a block diagram of a phased array antenna according to the prior art.

[0018] FIG. 1B is a block diagram of a base station antenna (BSA) according to the prior art.

[0019] FIG1C is a planar layout diagram of an RRVV base station antenna according to the prior art, showing the arrangement of two linear arrays of low-band radiating elements (X) and two linear arrays of high-band radiating elements (x).

[0020] Figure 2is a block diagram of a base station antenna (BSA) having multiple HPBW enhanced power divider circuits therein according to an embodiment of the present invention.

[0021] Figure 3A FIG. 4 is a block diagram of a HPBW reduction power divider circuit according to an embodiment of the present invention.

[0022] Figure 3B FIG. 1 is an electrical schematic diagram of a HPBW reduction power divider circuit according to an embodiment of the present invention.

[0023] Figure 3C FIG. 1 is an electrical schematic diagram of a HPBW reduction power divider circuit according to an embodiment of the present invention.

[0024] Figure 3D FIG. 1 is an electrical schematic diagram of a HPBW reduction power divider circuit according to an embodiment of the present invention.

[0025] Figure 3E FIG. 1 is an electrical schematic diagram of a HPBW reduction power divider circuit according to an embodiment of the present invention.

[0026] Figure 3F FIG. 4 is an electrical schematic diagram of a HPBW reduction power divider circuit including four -10 dB four-port directional couplers according to an embodiment of the present invention.

[0027] Figure 4A This is a plan view of the left column low-band radiating elements and the right column low-band radiating elements within a base station antenna according to an embodiment of the present invention, which shows how the phase shift feed (PSF) signals associated with the left column low-band radiating elements are provided to the left column low-band radiating elements and the right column low-band radiating elements at a reduced power level.

[0028] Figure 4B A plan view of the left column of low-band radiating elements and the right column of low-band radiating elements within a base station antenna according to an embodiment of the present invention is shown, which shows how the phase shift feed (PSF) signal associated with the left column of low-band radiating elements is provided to half of the radiating elements in the left column of low-band radiating elements and the right column of low-band radiating elements at a reduced power level.

[0029] Figure 4C A plan view of two columns of low-band radiating elements within a base station antenna according to an embodiment of the present invention shows how the phase-shifted feed (PSF) signal associated with the left column of low-band radiating elements is provided to a quarter of the radiating elements in the left column and the right column of low-band radiating elements at a reduced power level.

[0030] Figure 5 To compare the azimuth beamwidth profile (shown by the solid line) of the RRVV antenna (one column activated) with the Figure 3EFigure 1 compares the azimuth beamwidth profiles of the corresponding RRVV antennas of the power divider circuit, where k1 = 0.81 and k2 = 0.01.

[0031] Figure 6A FIG. 4 is a block diagram of a HPBW reduction power divider circuit according to an embodiment of the present invention.

[0032] Figure 6B FIG. 1 is an electrical schematic diagram of a HPBW reduction power divider circuit according to an embodiment of the present invention.

[0033] Figure 7A A plan view of left and right columns of low-band radiating elements within a base station antenna illustrating how multiple phase-shifted RF feed (PSF) signals derived from a first radio may be provided at different amplitudes to the left column of low-band radiating elements.

[0034] Figure 7B A plan view of a left column of low-band radiating elements and a right column of low-band radiating elements within a base station antenna according to an embodiment of the present invention shows how multiple phase-shifted RF feed (PSF) signals obtained from a first radio can be provided to the left column of low-band radiating elements and to a single radiating element in the right column of low-band radiating elements at different amplitudes.

[0035] Figure 7C A plan view of a left column of low-band radiating elements and a right column of low-band radiating elements within a base station antenna according to an embodiment of the present invention shows how multiple phase-shifted RF feed (PSF) signals obtained from a first radio can be provided to the left column of low-band radiating elements and to a single radiating element in the right column of low-band radiating elements at different amplitudes.

[0036] Figure 7D A plan view of a left column of low-band radiating elements and a right column of low-band radiating elements within a base station antenna according to an embodiment of the present invention shows how multiple phase-shifted RF feed (PSF) signals obtained from a first radio can be provided to the left column of low-band radiating elements and to three (3) radiating elements in the right column of low-band radiating elements at different amplitudes.

[0037] Figure 8 For Figures 7A-7C A graph comparing the -3dB beamwidth (HPBW) of a low-band radiating element array against frequency (GHz). DETAILED DESCRIPTION

[0038] The present invention will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. However, the present invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.

[0039] It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sectors, these elements, components, regions, layers, and / or sectors should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or sector from another region, layer, or sector. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer, or sector discussed below may be referred to as the second element, component, region, layer, or sector.

[0040] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an" and "said" are also intended to include plural forms. It will also be understood that the terms "comprise", "include", "have" and variations thereof, when used in this specification, refer to the presence of the described features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts and / or their groupings. On the contrary, the term "consisting of...", when used in this specification, refers to the described features, steps, operations, elements and / or parts, and excludes additional features, steps, operations, elements and / or parts.

[0041] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It will also be understood that terms such as those defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0042] Now refer to Figure 2 , a base station antenna (BSA) 20 according to an embodiment of the present invention is shown as including five (5) radiating elements (RE) per array. 11 -RE 15 、RE 21 -RE 25 ) of two linear arrays (ie, columns) defining a left low-band antenna (A1) and a right low-band antenna (A2). As shown, each pair of left and right radiating elements ((RE 11 -RE 21 )、(RE12 -RE 22 )……(RE 15 -RE 25 )) are responsive to a corresponding pair of modified phase-shifted feed signals ((PSF11, PSF21*), (PSF12, PSF22*) ... (PSF15, PSF25*)), which are generated by a corresponding power divider circuit (PDn = PD1, PD2, ... or PD5). Each of the power divider circuits PDn is responsive to a pair of phase-shifted feed (PSF) signals generated by a corresponding left phase shifter (Φ1-Φ5) and a right phase shifter (Φ1-Φ5). The left phase shifters (Φ1-Φ5) are collectively responsive to a first RF feed signal (FEED1) generated by a first transmitter TX1 and a phase control signal (CONTROL1) generated by a first controller. The right phase shifters (Φ1-Φ5) are collectively responsive to a second RF feed signal (FEED1) generated by a second transmitter TX2 and a phase control signal (CONTROL2) generated by a second controller.

[0043] Left low-band antenna A1 and right low-band antenna A2 may or may not transmit in the same frequency band. For example, in some cases, the two antennas A1 and A2 can be operated to support multiple-input multiple-output ("MIMO") transmission, in which the same signal is transmitted through multiple linear arrays of radiating elements after being "pre-distorted" (based on known characteristics of a given channel) so that the multiple transmitted signals (in the same frequency band) constructively combine at the receiver location. This "MIMO" technology can be very effective in reducing fading effects, signal reflections, etc.

[0044] In other cases, the two antennas A1 and A2 can be pointed in different directions to provide independent antenna beams in the same or different frequency bands. Thus, one low-band antenna (e.g., A1) can transmit in a first frequency band (e.g., the 700 MHz band), while the other low-band antenna (A2) can transmit in a different frequency band (e.g., the 800 MHz band). This means that the signals transmitted from A1 and A2 will not overlap in frequency.

[0045] As will be understood by those skilled in the art, the left (and right) phase shifters (Φ1-Φ5) can operate within a larger phase shifter circuit that generally performs multiple functions. First, this phase shifter circuit can perform 1x5 power splitting, so that the corresponding RF feed signal (e.g., FEED1, FEED2) can be further divided into five lower power feed signals, which are directly fed to the corresponding power divider circuit PDn. Second, the phase shifter circuit can generate phase slopes (e.g., -2°, -1°, 0°, +1°, +2° phase changes) across the individual feed signals, thereby producing the lower power feed signals as phase-shifted feed signals (PSFs). Advantageously, this phase slope, which can create a desired electronic "down tilt" on the elevation pattern of the generated antenna beam, can be remotely controlled and adjusted.

[0046] Moreover, as referenced Figure 3E As highlighted below, according to some alternative embodiments of the present invention, a single power divider circuit can be placed between each feed signal transmitter (TX1, TX2) and the corresponding phase shifter (Φ1-Φ5), resulting in an improvement in half-power beamwidth (HPBW). However, when the two antennas A1 and A2 are operated to support multiple-input multiple-output ("MIMO") transmission, the same downtilt will be applied to both antennas. In addition, when one antenna covers one frequency band (e.g., the 700 MHz band) and the other antenna covers another frequency band (e.g., the 800 MHz band), the downtilt will be different on the two bands. In both applications, Figure 3E The embodiment relative to Figure 2 Examples and Figures 4B-4C Furthermore, due to the fact that a relatively high amount of signal energy may be lost to ground (GND) within the power divider circuit 30e, Figure 3E The embodiment of may produce relatively high signal loss. However, as Figure 5 As shown, the figure shows the -180° to +180° beamwidth profile of the RRVV antenna (one column is activated) using Figure 3E Comparing the beamwidth profiles of the corresponding RRVV antennas with the power divider circuits in the graphs, HPBW improvement can be achieved for the RR array of RRVV antennas using a single power divider circuit 30e.

[0047] Now refer to Figure 3A , the power divider circuit 30a can be used to perform Figure 2The operation of the power divider circuit PD1-PD5 is shown as generating a pair of modified phase-shifted feed signals PSF1n* and PSF2n* by intentionally cross-coupling a pair of phase-shifted input feed signals PSF1n and PSF2n, which can be generated by Figure 2 The respective phase shifters (Φ) associated with the spaced-apart antennas A1 and A2 in the BSA 20 are shown. n ) is generated. Specifically, the modified phase-shifted feed signal PSF1n* is generated as a first combination of the first phase-shifted input feed signal PSF1n and the second phase-shifted input feed signal PSF2n. According to some embodiments of the present invention, the modified phase-shifted feed signal PSF1n* is generated according to the following relationship: PSF1n*=(k1)PSF1n+(k2)PSF2n, where PSF1n represents the first RF feed signal, PSF2n represents the second RF feed signal, k1 is the first power conversion coefficient, k2 is the second power conversion coefficient, and where 0.7≤k1≤0.9 and 0.0026≤k2≤0.027. Similarly, the modified phase-shifted input feed signal PSF2n* is generated as follows: PSF2n*=(k1)PSF2n+(k2)PSF1n, where k1 is the first power conversion coefficient and k2 is the second power conversion coefficient. In an alternative embodiment of the present invention, these first power conversion coefficients k1 and second power conversion coefficients k2 associated with the generation of the modified phase-shifted input feed signal PSF2n* may be provided as a third power conversion coefficient k1* (where k1*≠k1) and a fourth power conversion coefficient k2* (where k2*≠k2), and where 0.7≤k1*≤0.9 and 0.0026≤k2*≤0.027. Finally, despite the Figure 3A The cross-coupling operations shown are performed on a phase-shifted feed signal (PSF), but these operations can be performed on a phase-shifted feed signal (PSF) such as that provided by Figure 3E This is performed "globally" on each of the feed signals FEED1, FEED2 generated by the transmitters shown.

[0048] As Figures 3B-3D As shown in the embodiment of FIG, a plurality of alternative circuit designs can be used to perform the Figure 3A The operation of the power divider circuit 30a is shown. For example, as shown by Figure 3B As shown in the power divider circuit 30b, two pairs of 4-port cascaded directional couplers ((C 11 -C 12 )、(C 21 -C 22 )) can be accessed through R 11 、R 12 、R 21 、R 22Cross-coupled with a single-port resistor termination, the phase-shifted input feed signals PSF1n, PSF2n are converted into modified phase-shifted input feed signals PSF1n*, PSF2n*.

[0049] According to some embodiments of the present invention, Figure 3B Directional coupler C 11 、C 12 、C 21 and C 22 can be configured as a four-port directional coupler with the same characteristics (e.g., a -10dB coupler), where R 11 、R 12 、R 21 、R 22 It can be 50 ohms. Figure 3B Shown and Figure 3F As shown in the power divider circuit 30f, if the directional coupler C 11 、C 12 、C 21 and C 22 is the same as the -10dB coupler, then coupler C 11 90% of the energy associated with the first phase-shifted input feed signal PSFn1 is transferred to coupler C 12 and couples 10% of the energy associated with the first phase-shifted input feed signal PSFn1 to coupler C 22 , where 90% of the coupled 10% signal will pass through the terminal resistor R 22 is passed to ground (and lost), and 10% of the coupled 10% signal (ie, 1% = 0.01, or -20 dB) will be provided to C 22 The output of the coupler C is the signal component of PSF2n*. 21 90% of the energy associated with the second phase-shifted input feed signal PSFn2 is transferred to coupler C 22 and couples 10% of the energy associated with the second phase-shifted input feed signal PSFn2 to coupler C 12 , where 90% of the coupled 10% signal will pass through the terminal resistor R 12 is passed to ground (and lost), and 10% (i.e., 1%) of the coupled 10% signal will be available to C 12 In a similar manner, at coupler C 12 90% of the 90% PSF1n signal received at the input of will be passed as "(0.81)PSF1n", ie the main energy component of PSF1n*, and will be transmitted to the coupler C. 2290% of the 90% PSF2n signal received at the input of will be passed as the main energy component of "(0.81)PSF2n", ie, PSF2n*.

[0050] Figure 3C An alternative power divider circuit 30c is shown, which uses four Wilkinson power dividers WPD 11 、WPD 12 、WPD 21 and WPF 22 (Including resistor R * 11 、R * 12 、R * 21 and R * 22 ) instead Figure 3B The directional coupler C shown in 11 、C 12 、C 21 and C 22 These resistors R * 11 、R * 12 、R * 21 and R * 22 The values of may be unequal in some embodiments of the present invention to achieve asymmetric coupling when k1 and k1* are unequal and k2 and k2* are unequal. Figure 3D In the embodiment of the present invention, the power divider circuit 30d is shown as including ( Figure 3B A pair of directional couplers C 11 、C 21 and( Figure 3C A pair of Wilkinson power dividers (WPD) 12 and WPF 22 Each of these embodiments advantageously supports the above Figure 3A Emphasizes cross-coupling of feed signal energy.

[0051] As Figure 3F and Figures 4A-4C As shown, the left column low-band radiating elements and the right column low-band radiating elements can use different numbers of cross-coupled power divider circuits 30f in the base station antennas 40a, 40b and 40c to achieve different levels of half-power beamwidth HPBW reduction. Figure 4AIn FIG, all eight phase-shifted feed signals PSF1n associated with the left array of radiating elements may be generated at 0.979 or 0.5 power levels and then undergo cross-coupling to facilitate reduced power levels of 0.979 (0.81) and 0.5 (0.81) for the left array and reduced power levels of 0.979 (0.01) and 0.5 (0.01) for all radiating elements in the right array at 1% coupling. This 1% coupling is a form of "intentional" signal interference that achieves a perceptible reduction in HPBW with minimal adverse consequences for the integrity of the main feed signal associated with the right array of radiating elements. In contrast, in FIG, Figure 4B In the example, only the middle four radiating elements in the left and right arrays receive the coupled signal, while in Figure 4C However, each of these "intentional" cross-coupling embodiments can be used to advantage to reduce HPBW to varying degrees at varying levels of power efficiency.

[0052] Now refer to Figure 6A , an alternative power divider circuit 60a is illustrated as generating a pair of modified phase-shifted feed signals PSF1n* and PSF2n* by intentionally cross-coupling a pair of phase-shifted input feed signals PSF1n and PSF2n, which can be generated by Figure 2 The respective phase shifters (Φ) associated with the spaced-apart antennas A1 and A2 in the BSA 20 are shown. n )generate. Specifically, Figure 6A The modified phase-shifted feed signal PSF1n* is generated as a first combination of the first phase-shifted input feed signal PSF1n and the second phase-shifted input feed signal PSF2n. According to some embodiments of the present invention, the modified phase-shifted feed signal PSF1n* is generated according to the following relationship: PSF1n*=(k1)PSF2n+(k2)PSF1n, where PSF1n represents the first RF feed signal, PSF2n represents the second RF feed signal, k1 is the first power conversion coefficient, k2 is the second power conversion coefficient, and where 0.7≤k1≤0.9 and 0.0026≤k2≤0.027. Similarly, the modified phase-shifted input feed signal PSF2n* is generated as follows: PSF2n*=(k1)PSF1n+(k2)PSF2n, where k1 is the first power conversion coefficient and k2 is the second power conversion coefficient. In some other embodiments of the present invention, the first power conversion coefficient k1 may be specified as: 0.7≤k1, and the second power conversion coefficient k2 may be specified as: k2≤0.05.

[0053] Figure 6A An embodiment of the power divider circuit 60a may be configured to include two pairs of cascaded directional couplers (C 11-C 12 )、(C 21 -C 22 )), these two pairs of cascaded directional couplers are connected via Figure 6B The power divider circuit 60b shown in R 11 、R 12 、R 21 、R 22 are cross-coupled to each other and include single-port resistor terminations. Figure 6B Directional coupler C 11 、C 12 、C 21 and C 22 can be configured as a four-port directional coupler with the same characteristics (e.g., a -10dB coupler), where R 11 、R 12 、R 21 、R 22 It can be 50 ohms. Figure 6B As shown, if the directional coupler C 11 、C 12 、C 21 and C 22 is the same as the -10dB coupler, then coupler C 11 90% of the energy associated with the first phase-shifted input feed signal PSFn1 is transferred to coupler C 12 and couples 10% of the energy associated with the first phase-shifted input feed signal PSFn1 to coupler C 22 , where 90% of the coupled 10% signal will pass through the terminal resistor R 22 is passed to ground (and lost), and 10% of the 10% of the signal coupled (i.e. 1% = 0.01, or -20 dB) will be provided to C 22 The output of coupler C is as the secondary signal component of PSF1n*. 21 90% of the energy associated with the second phase-shifted input feed signal PSFn2 is transferred to coupler C 22 and couples 10% of the energy associated with the second phase-shifted input feed signal PSFn2 to coupler C 12 , where 90% of the coupled 10% signal will pass through the terminal resistor R 12 is passed to ground (and lost), and 10% (i.e., 1%) of the coupled 10% signal will be available to C 12 The output of (as the secondary signal component of PSF2n*). In a similar way, at coupler C 1290% of the 90% PSF1n signal received at the input of will be passed as "(0.81)PSF1n", ie, the main energy component of PSF2n*, and will be transmitted to the coupler C. 22 90% of the 90% PSF2n signal received at the input of will be passed as "(0.81)PSF2n", that is, the main energy component of PSF1n*. Based on this illustrated configuration, Figure 6B The power divider circuit 60b is connected with Figure 3B The power divider circuit 30b operates in the same manner, but has crossed outputs.

[0054] Now refer to Figures 7A-7D , provides a comparison of four approaches illustrating alternative techniques for driving a single array of radiating elements (e.g., low-band radiating elements) with a first plurality of radio frequency (RF) feed signals derived from a first RF input feed signal generated by an RF transmitter (e.g., a radio). Figure 2 As illustrated and described herein above, the plurality of phase-shifted feed signals PSF11-PSF15, PSF21-PSF25 may be generated by a corresponding plurality of phase shifters that receive input feed signals from respective RF feed sources, including a first radio and a second radio (e.g., TX1, TX2).

[0055] exist Figure 7A , a plan view of the left and right columns of radiating elements within a base station antenna 70a is provided showing how a first plurality of phase-shifted RF feed signals (PSF1n) derived from a first radio may be provided at different amplitudes (and different relative phases) to the left column six (6) low-band radiating elements, and without Figure 2 、 3A and any intermediate power divider circuits (PDn) shown in FIG6A. Based on this configuration, the relative amplitudes of the first plurality of phase-shifted RF feed signals (PSF1n) vary according to the following distribution (from the "lower" left radiating element in the left column to the "upper" left radiating element in the left column): PSF11 = 0.13, PSF11 = 0.23, PSF13 = 0.25, PSF14 = 0.21, PSF15 = 0.065, PSF16 = 0.065.

[0056] On the contrary, Figure 7B, a plan view of left and right columns of radiating elements within a base station antenna 70b according to an embodiment of the present invention is provided, illustrating how a first plurality of phase-shifted RF feed signals (PSF1n) derived from a first radio may be provided at varying amplitudes to six (6) low-band radiating elements in the left column, and also to a single radiating element at the end of a second column of radiating elements. Specifically, a corresponding pair of left and right radiating elements 72b at the "upper" end of the antenna 70b may be provided with signals from, for example, Figure 3A The single power divider circuit PDn 30a modifies the phase-shifted RF feed signal PSF16 to obtain a corresponding pair of reduced power signal drivers, where PSF16=0.065, PSF16*=0.065×0.81, and PSF26*=0.065×0.01. (See also Figure 3B 、 3F PDn 30b, PDN 30f). Therefore, Figure 7B The feed signal driving example shown corresponds to the Figures 4A-4C The related art shown only uses one power divider circuit PDn (eg, 30a, 30b, 30f).

[0057] Then, as Figure 7C 1, there is provided a base station antenna 70c according to an embodiment of the present invention, which shows how a first plurality of phase-shifted RF feed signals (PSF1n) derived from a first radio may be provided at different amplitudes to a left column of six (6) low-band radiating elements, and also to a single radiating element at the end of a second column of radiating elements. Specifically, a corresponding pair of left and right radiating elements 72c at the "upper" end of the antenna 70c may be provided with signals from Figures 6A-6B The phase-shifted RF feed signal PSF16 modified by the single power divider circuits PDn 60a, 60b results in a corresponding pair of reduced power signal drivers, where PSF16 = 0.065, PSF16* = 0.065 x 0.01, and PSF26* = 0.065 x 0.81. Thus, as shown, by reversing the amplitude of the signal provided between the left and right radiating elements in pair 72c relative to pair 72b (0.81 versus 0.01), the power of the radiator is reduced by Figure 7C The feed signal driving example shown is different from the Figure 7B Based on this configuration, the same 498mm housing can be used to provide a 600MHz antenna (band from 617MHz to 896MHz) as an RRVV antenna (e.g., 698MHz-960MHz). Figures 7A-7C The base station antennas 70a, 70b and 70c may have a width of 498 mm and a length of 1828 mm.

[0058] Finally, as Figure 7D As shown, a base station antenna 70d is provided, which shows an embodiment of the present invention. Figures 3A-3B How can the first power divider circuit (30a, 30b, 30f) of 3F be connected with Figures 6A-6B The second power divider circuit (60a, 60b) is combined to achieve further HPBW narrowing. As shown, the first pair of side-by-side radiating elements 72d1 at the ends of the first column of radiating elements and the second column of radiating elements can receive signals from the second power divider circuit (60a, 60b), while the other two pairs of side-by-side radiating elements 72d2, 72d3 can receive signals from the corresponding first power divider circuit (30a, 30b, 30f).

[0059] Now refer to Figure 8 , provides Figures 7A-7B A graph comparing the relative half power beam width (HPBW) (y-axis) as a function of frequency (x-axis) between embodiments of the present invention, wherein a single power divider circuit PDn is used at the end of the antenna 70b (see, for example, Figure 3A 、 3B and 30a, 30b, 30f of 3F) to achieve a relatively small reduction in HPBW (≈2°), but by using a single "reverse output" power divider circuit PDn at the end of antenna 70c (see e.g. Figures 6A-6B 60a, 60b) to achieve a relatively large reduction in HPBW (≈16°).

[0060] In the drawings and specification, there have been disclosed typical preferred embodiments of the invention, and although specific terms are employed, they are used in a generic and descriptive sense and not for purposes of limitation, the scope of the invention being set forth in the following claims.

Claims

1. An antenna array, comprising: a first array of radiating elements responsive to a first plurality of radio frequency (RF) feed signals originating from a first radio; a second array of radiating elements responsive to a second plurality of RF feed signals originating from a second radio; as well as and a first power divider circuit configured to drive the first radiating element in the second column of radiating elements with 70% to 90% of energy associated with the first RF feed signal in the first plurality of RF feed signals and to drive the first radiating element in the first column of radiating elements with 0.26% to 2.7% of energy associated with the first RF feed signal in the first plurality of RF feed signals.

2. The antenna array according to claim 1, wherein: A first radiating element in the first column of radiating elements extends opposite to a first radiating element in the second column of radiating elements.

3. The antenna array according to claim 2, wherein: The first power divider circuit is further configured to drive the first radiating element in the first column of radiating elements with 70% to 90% of the energy associated with the first RF feed signal in the second plurality of RF feed signals, and to drive the first radiating element in the second column of radiating elements with 0.26% to 2.7% of the energy associated with the first RF feed signal in the second plurality of RF feed signals.

4. The antenna array according to claim 3, further comprising: and a second power divider circuit configured to drive the second radiating element in the first column of radiating elements with 70% to 90% of the energy associated with the second RF feed signal in the first plurality of RF feed signals, and to drive the second radiating element in the second column of radiating elements with 0.26% to 2.7% of the energy associated with the second RF feed signal in the first plurality of RF feed signals.

5. The antenna array according to claim 4, wherein: The second power divider circuit is further configured to drive the second radiating element in the second column of radiating elements with 70% to 90% of the energy associated with the second RF feed signal in the second plurality of RF feed signals, and to drive the second radiating element in the first column of radiating elements with 0.26% to 2.7% of the energy associated with the second RF feed signal in the second plurality of RF feed signals. The antenna array according to claim 3 , wherein: A second radiating element in the first column of radiating elements receives all energy associated with a second RF feed signal in the first plurality of RF feed signals; and wherein the second radiating element in the second column of radiating elements receives all energy associated with the second RF feed signal in the second plurality of RF feed signals.

7. The antenna array according to claim 1, further comprising: a first phase shifter configured to generate the first plurality of RF feed signals in response to a first RF input feed signal generated by the first radio, the first plurality of RF feed signals being phase-shifted relative to one another; as well as A second phase shifter is configured to generate the second plurality of RF feed signals in response to a second RF input feed signal generated by the second radio, the second plurality of RF feed signals being phase shifted relative to one another.

8. An antenna array, comprising: a first array of radiating elements responsive to a first plurality of RF feed signals originating from a first radio frequency (RF) transmitter; a second array of radiating elements responsive to a second plurality of RF feed signals originating from a second RF transmitter; as well as and a first power divider circuit configured to: (i) drive a first radiating element in the second array of radiating elements with 70% to 90% of the energy associated with a first RF feed signal in a first plurality of RF feed signals; (ii) drive the first radiating element in the first array of radiating elements with 0.26% to 2.7% of the energy associated with the first RF feed signal in the first plurality of RF feed signals; (iii) drive the first radiating element in the first array of radiating elements with 70% to 90% of the energy associated with the first RF feed signal in the second plurality of RF feed signals; and (iv) drive the first radiating element in the second array of radiating elements with 0.26% to 2.7% of the energy associated with the first RF feed signal in the second plurality of RF feed signals.

9. The antenna array according to claim 8, wherein: A second radiating element in the first array of radiating elements receives all energy associated with a second RF feed signal in the first plurality of RF feed signals; and wherein the second radiating element in the second array of radiating elements receives all energy associated with a second RF feed signal in the second plurality of RF feed signals.

10. The antenna array according to claim 8, further comprising: and a second power divider circuit configured to drive a second radiating element in the first array of radiating elements with 70% to 90% of energy associated with a second RF feed signal in the first plurality of RF feed signals, and to drive a second radiating element in the second array of radiating elements with 0.26% to 2.7% of energy associated with the second RF feed signal in the first plurality of RF feed signals.

11. The antenna array according to claim 9, wherein: The first radiating element array and the second radiating element array are respectively a first radiating element linear array and a second radiating element linear array.

12. An antenna array, comprising: a first array of radiating elements comprising a first plurality of radiating elements responsive to a first plurality of RF feed signals originating from a first radio; a second array of radiating elements comprising a second plurality of radiating elements responsive to a second plurality of RF feed signals originating from a second radio; as well as and a first power divider circuit configured to drive the first radiating element at the first end of the second column of radiating elements with 70% to 90% of energy associated with the first RF feed signal in the first plurality of RF feed signals, and to drive the first radiating element at the first end of the first column of radiating elements with 0.26% to 2.7% of energy associated with the first RF feed signal in the first plurality of RF feed signals.

13. The antenna array according to claim 12, wherein: The first power divider circuit is further configured to drive the first radiating element in the first column of radiating elements with 70% to 90% of the energy associated with the first RF feed signal in the second plurality of RF feed signals, and to drive the first radiating element in the second column of radiating elements with 0.26% to 2.7% of the energy associated with the first RF feed signal in the second plurality of RF feed signals.

14. The antenna array according to claim 13, wherein: A second radiating element in the first column of radiating elements is driven with all energy associated with a second RF feed signal in the first plurality of RF feed signals and none of the energy associated with a second RF feed signal in the second plurality of RF feed signals; and wherein the second radiating element in the second column of radiating elements is driven with all energy associated with a second RF feed signal in the second plurality of RF feed signals and none of the energy associated with the second RF feed signal in the first plurality of RF feed signals.

15. The antenna array according to claim 13, wherein: A second radiating element at a second end of the first column of radiating elements is driven with all energy associated with a second RF feed signal in the first plurality of RF feed signals and none of the energy associated with a second RF feed signal in the second plurality of RF feed signals; and wherein the second radiating element at a second end of the second column of radiating elements is driven with all energy associated with a second RF feed signal in the second plurality of RF feed signals and none of the energy associated with the second RF feed signal in the first plurality of RF feed signals.

16. The antenna array according to claim 13, wherein: The first power divider circuit includes a cascaded first pair of power dividers cross-coupled with a cascaded second pair of power dividers.

17. The antenna array according to claim 16, wherein: Each power divider of the cascaded first pair of power dividers and each power divider of the cascaded second pair of power dividers is selected from the group consisting of a directional coupler, a branch line coupler, a Wilkinson power divider, and a reactive T-splitter, and combinations thereof.

18. The antenna array according to claim 16, further comprising: and a second power divider circuit configured to drive the second radiating element in the first column of radiating elements with 70% to 90% of the energy associated with the second RF feed signal in the first plurality of RF feed signals, and to drive the second radiating element in the second column of radiating elements with 0.26% to 2.7% of the energy associated with the second RF feed signal in the first plurality of RF feed signals.

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